The present invention relates to compositions and methods for treating conditions associated with angiogenesis. In particular the present invention relates to multi-unit complexes of tRNA synthetase fragments and uses thereof diverse multi-unit complexes including a tRNA synthetase fragment compositions and methods for modulating angiogenesis polynucleotides encoding tRNA synthetase fragments and uses thereof antibodies and epitopes specific to tRNA synthetase fragments variants of tRNA synthetase fragments and uses thereof methods for treating angiogenesis methods for screening for anti-angiogenic agents methods of modulating angiogenesis kits for modulating angiogenesis and business methods for modulating angiogenesis. Preferably the tRNA synthetase fragments are tryptophanyl tRNA synthetase fragments, and more preferably human tryptophanyl tRNA synthetase fragments.
